You can find the volume with or without calc. Which do you wanna do?.
Volume indicates 3-D. I suppose you mean a cylindrical tank of radius 13/20 and length 21/10?.
Here's the calc method for the volume(shaded portion) of the cylindrical tank of radius 13/20 and length 21/10.
You can do it without by using the formula for the middle ordinate.
You are given the heighth of the segment, 1/5.
Solving, we see
Now, sub that into the formula for the segment of a circle:
This is the area of the segment, you need the shaded portion.
Multiply this by the length, 21/10.
You get 2.5154. Same as above